The present invention relates to a machine for producing flaskless moulds.
Document EP-0 468 355 discloses a conventional moulding forming machine of the above-mentioned type. This moulding machine is of a type in which a cope flask, a pattern plate and a drag flask are capable of rotating over an angle of 90xc2x0 between a horizontal position and a vertical position. The horizontal position is associated with inserting the pattern plate between the cope and drag flask before the sand charging and compacting step and is associated with the removing of the pattern plate and the discharging of the cope and drag after the charging and compacting step. The sand charging and compacting step is performed with the cope flask, drag flask and pattern plate in the vertical position. The prior art moulding machine uses a first squeeze plate for compacting the sand in the cope flask (the upper flask by definition) and a second squeeze plate for compacting the sand in the drag flask (the lower flask by definition). The second squeeze plate is inserted into the drag flask when the latter is in the vertical position. Because of the rotating movement of the drag flask with respect to the fixed second squeeze plate, it is difficult to align the drag flask with the second squeeze plate in a precise and reproducible manner. The exact alignment in the prior art machine has to be carried out by the compression frame, which has already another important function, namely the transmission of the force for compacting the sand from one squeeze plate to the other. Therefore, the above described second squeeze plate cannot always be smoothly introduced into the drag flask due to deviations in the alignment of the two components.
It is the object of the present invention to provide a moulding machine for producing flaskless moulds of the kind referred to above, with which it is possible to overcome the disadvantages mentioned above and which allows easier alignment of the second squeeze plate with the drag flask, thus resulting in a simpler construction of the components of the machine and in higher quality drags and copes. This object is achieved with a machine for producing flaskless moulds in which the cope flask with a first squeeze plate and the drag flask with an associated second squeeze plate are supported by a swing frame and rotatable in unison between the horizontal position and the vertical position. With this arrangement, the alignment function of the compression frame is transferred to the swing frame which takes care of all alignment, whereas the compression frame is only constructed to transmit the relatively large forces related to the compacting of the sand. Thus, the second squeeze plate is always kept in alignment, avoiding problems associated with reproducibility of position. The lower and upper squeeze plates as well as the drag and cope flask are rotated over approximately 90xc2x0 to take their vertical position in which the cope flask and drag flask are filled with sand. After the sand-filling, the compacting of the sand also takes place in, the vertical position.
According to a further embodiment, the swing frame which carries the squeeze plates and the flasks is received in an opening in the compression frame.
According to another embodiment of the invention, the drag flask is arranged to be movable up and down with respect to the fixed cope flask when the cope flask and drag flask are in their horizontal position.
In an embodiment of the present invention, the second squeeze plate is inserted in the drag flask when the cope flask and drag flask are in their horizontal position.
According to a further embodiment, the second squeeze plate serves as a table to receive and lower the superposed cope and drag when the latter are discharged from the cope flask and drag flask, thus doing away with the need for an additional transport table.
According to a further embodiment, the sand-charging openings of the respective cope flask and drag flask will, when the latter are moved into their vertical position, engage the sand-blowing nozzles of the blowhead.